Process of making potash alum.



UNITED STATES PATENT OFFICE.

EDWARD HART, OF EAST 0N, PENNSYLVANIA.

PROCESS OF MAKING- P OTASH No Drawing.

To' all whom it mag concern:

Be it known that I, EDWARD IlAR'r, a citizen of the United States, andresident of Easton, Pennsylvania, have invented certain new and usefulImprovements in the Process of Making Potash Alum, of which thefollowing is a specification.

My invention relates to the manufacture of potash and other products,and also of a pure silica, from the decomposition of feldspar and likerocks, the object thereof being to provide a simple, efficient andeconomical method which. can be successfully-practised on any desiredscale.

I have discovered that when feldspar or similar rock is mixed withpotassium or sodium sulfate and carbon and heated to fusion in asuitable furnace there is formed a soluble glass consisting of apotassium or sodium. aluminum silicate. This glass may readily bedecomposed by the addition ofa suitable acid such as sulfuric acidforming whatis practically a pure silica and also a solution from whichpotassium and aluminum may be obtained in the form of common otash alum,leaving a mother liquor containing sulfates of potassium or sodium andaluminum, some free sulfuric acid, and other sulfates formed fromimpurities in the feldspar such as iron sulfate and sodium or potassiumsulfate. From this mother liquor, by suitable processes hereinafter morefully described, I obtain aluminate of soda or potash, or both.

The following example will illustrate in detail one specific method ofcarryin out my invention :To 278 parts by weight of orthoclase feldspar(KAlSi O, and impurities) I add 174: parts. by weight of potassiumsulfate (11 80,), or 142' parts, by weight, of sodium sulfate (Na. ,SO,)and 24 parts, by weight, of carbon, or its equivalent amount in the formof coke, anthracite coal, or other carbonaceous material. The mixture isfused in a suitable furnace, for instance a blast furnace, areverbcratory furnace or an electric furnace to a suitable temperature,for instance from l300 to 1500 C. The glassthusproduced is finelypulverized and treated with a suitable acid, such as sulfuric acid. Ifind that good results are obtained by using a mixture of one part ofoil of vitriol with one partof water. The amount to be 'used of thissolution varies somewhat according to the nature of the feldsparemployed and also to the sulfate Specification of Letters Patent.

silica (SiO Patented May 20, 1913.

Application filed March 27, 1911. Serial No. 617,008.

employed, but will be approximately 140 parts by weight of the solutionto 100 parts by weight of the glass. The mixture of glass and acid isthen evaporated and then heated to a temperature of about 150 C.

for at least an hour so as to decompose the glass completely and to formuncombmed then boiled with water, and the insoluble silica is separatedby filtration or in any other manner well known to those skilled in theart. The insoluble silica thus obtained usually contains carbon and somewater. It is heated to redness to drive off the water and to burn thecarbon, thus leaving an almost pure silica quite free fromiron, and

suitable foruse in the manufacture of pot-.

tery and for other purposes. The filtrate, or remaining solution, isevaporated to the The resulting product is proper degree so as todeposit on .cooling- I the potasslum and aluminum in the form of commonpotash alum crystals substantially all the other salts such as iron,potas-.

sium, sodium and aluminum' sulfates, to-

gether with some free sulfuric acid remaining in the solution in themother li uor. This mother liquor is then evaporate to dryness and fusedwith a suitable amount of carbon. Large quantities of sulfur are givenoil", and the residue consists chiefly of aluminate of soda or potashorboth, or of one or more of these substances together with alumina. Ifwater be added to the residue thealuminate of soda or potash will belargely dissolved, leaving an insoluble residue consisting mainly ofiron sulfid and possibly some alumina.

The solution may be decanted or filtered off and the aluminate of sodaor potash recovered by evaporation, thus efi'ecting a perfect separationof the iron and the alumina contained inthe original feldspar.

The residue if sutliciently rich in alumina,

may be added to the first fusion, replacing a portion of the potassiumor-sodium sulf fate. In fusing this mixture with coal I do not confinemyself to any definite proportions, but find that when sodium sulfate 1sused in the original fusion with the feld spar a satisfactory result maybe obtained aluminum silicate.

'When I speak in my claims of employing in my reactions sodium sulfateand car bon I intend to include any equivalent substance or substances,as for instance the product of the reaction between these twosubstances, or potassium sulfate in place of sodium sulfate.

- I claim:

1. The process hereinbefore described L which, com rises heatingfeldspar with sul- Ifateof' so aan "carbon, and treating the prod t'witha suitable acid.

2. 'Fhe process hereinbefore described which comprises heating feldsparwith sulfate of soda and. carbon, and treating the product with sulfuricacid.

3. The process hereinbefore described which comprises heating feldsparwith sulfate of soda and carbon, treating the prodnot with a suitableacid, and se aratin the soluble and the insoluble pro nets 0 thereacti0n..

4. The process hereinbefore described which comprises heatingfeldsparwith sulfate of soda and carbon, treating the product with sulfuricacid, and separating the soluble and the insoluble products of thereaction.

5. The process hereinbefore described which comprises heating feldsparwith sulfate of soda and carbon, treatmg the product with sulfuric acid,separatin the soluble and the insoluble products-0% the reac- 'tion' andremoving from the soluble product the potash alum.

6. The process hereinbefore described which comprises heating feldsparwith sulfate of soda and carbon, treating the product with sulfuricacid, separating the soluble and the insoluble products of the reactionand removing from the soluble product the potash alum and fusing theremainin sodium sulfate and aluminum sulfate wit carbon. 3

In witness whereof I have hereunto' set my hand in the presence. of twosubscribing witnesses.

EDWARD HART. Witnesses FRITZ v. BRIEsEN, FRANK F. KIRKPATRICK.

Qoplu of this patent fly bfo btained forflve cents each, byaddressingthe Commissioner of latent. Washington, D. 0.

